MetroLink  is the light rail transit system in the Greater St. Louis area of Missouri and the Metro East area of Illinois. The system consists of two lines (Red Line and Blue Line) connecting Lambert-St. Louis International Airport and Shrewsbury, MO with Scott Air Force Base near Shiloh, Illinois through downtown St. Louis. The system has 37 stations and carries an average of over 53,000 people each weekday.

http://www.metrostlouis.org/